When they first called I accidentally rejected the call and called back to see if it was important.  I got a message on my phone of "wrong number" and the "bee, boo, bee" sound.  I thought that was strange, but let it go.  Then they called again a day or so later.  I picked up, no one spoke and there was no sound.  I said, "Hello, Hello, Hello, Hello" There was no response or sound on the other end, and I ended the call.

This happened in the past week.

call but no message left, so some form of Spam, political, telemarketer or whatever.  For them, not me.  Now blocked.  Thank you Verizon for offering unlimited cell blocking

I didn't answer the call, but I called it back and I got the message, "Sorry, your call cannot be completed as dialed...."

Multiple calls over week +.  No message, now blocked.
Spam reporters on another site ID company as Green Energy.  Telemarketers who don't give up, no matter the request.